Reviewing the Stylebits Parameters

The four parameters of stylebits are AddBit, RemoveBit, AddExtendedBit, RemoveExtendedBit. For a review of these four parameters, and an introduction to Stylebits in general, please read [Stylebits Corner - An Introduction].

Graphic Windows and Scrollbars

A window opened for graphics automatically includes both a vertical and a horizontal scrollbar. Scrollbars are useful when a larger image is being used in a smaller space. The user simply scrolls to the desired area. This small snippet illustrates both a regular window and a graphics window.

    Nomainwin
    WindowWidth = 300
    WindowHeight = 400
    UpperLeftX = 50
    UpperLeftY = 50
    Open "A Regular Window" for Window as #w
    #w, "Trapclose EndDemo"

    UpperLeftX = Int(DisplayWidth/2) + 50
    Open "A Graphics Window" for Graphics as #g
    #g, "Trapclose EndDemo"

    Wait

    Sub EndDemo handle$
        Close #w
        Close #g
        End
        End Sub

Adding a Scrollbar to a Graphicbox

A graphicbox imbedded into a regular window lacks scrollbars. Graphics drawn or loaded beyond the viewing area of the graphicbox can not be seen. Stylebits allows scrollbars to be added to the graphicbox. The graphicbox now has the same functionality as the graphics window. Because the scrollbars consume graphicbox space, you will need to adjust the size of your graphicbox accordingly. An increase of 17 pixels works well.

    Nomainwin
    WindowWidth = 700
    WindowHeight = 400
    UpperLeftX = Int((DisplayWidth - WindowWidth)/2)
    UpperLeftY = Int((DisplayHeight - WindowHeight)/2)
'Graphicbox #1 uses no stylebits
    Graphicbox #w.g1, 20, 20, 300, 300
'Graphicbox #2 has scrollbars courtesy of stylebits
    Stylebits #w.g2, _WS_VSCROLL or _WS_HSCROLL, 0, 0, 0
    Graphicbox #w.g2, 350, 20, 317, 317

    Open "Two Graphicboxes" for Window as #w
'Draw some graphics in each graphicbox
    #w.g1, "Down; Fill Darkblue; Size 3"
    #w.g2, "Down; Fill Darkblue; Size 3"
    For i = 1 to 1000
        redHue = Int(Rnd(1) * 256)
        greenHue = Int(Rnd(1) * 256)
        blueHue = Int(Rnd(1) * 256)
        #w.g1, "Color ";redHue;" ";greenHue;" ";blueHue
        #w.g2, "Color ";redHue;" ";greenHue;" ";blueHue
        x1 = Int(Rnd(1) * 2000)
        y1 = Int(Rnd(1) * 1200)
        lngth = Int(Rnd(1) * 50) + 25
        x2 = x1 + lngth
        y2 = y1 + Int(Rnd(1) * lngth) + 10
        #w.g1, "Line ";x1;" ";y1;" ";x2;" ";y2
        #w.g2, "Line ";x1;" ";y1;" ";x2;" ";y2
        #w.g1, "Flush"
        #w.g2, "Flush"
    Next i
    Wait

    Sub EndDemo handle$
        Close #w
        End
        End Sub

Stylebits and API

There may be a time when you want to program the scrolling of scrollbars rather than waiting for the user to do a manual scroll. Scrollbars can easily be manipulated using the API call "SendMessageA" and a few Windows constants. This demo uses buttons to demonstrate a way to code scrolling. _SB_LINE scrolls 8 pixels while _SB_PAGE scrolls 64 pixels. These values may change depending upon other attributes you assign your window.

'Adding Scrollbars and Scrolling a Graphicbox
    Nomainwin
    WindowWidth = 600
    WindowHeight = 400
    UpperLeftX = Int((DisplayWidth - WindowWidth)/2)
    UpperLeftY = Int((DisplayHeight - WindowHeight)/2)
    GraphicBox #1.g, 0, 0, 500, 365
    Stylebits #1.g, _WS_HSCROLL or _WS_VSCROLL, 0, 0, 0
    Button #1.scrollUp, "Scroll Up", Scroll, UL, 515, 40, 62, 50
    Stylebits #1.scrollUp, _BS_MULTILINE, 0, 0, 0
    Button #1.scrollDown, "Scroll Down", Scroll, UL, 515, 120, 62, 50
    Stylebits #1.scrollDown, _BS_MULTILINE, 0, 0, 0
    Button #1.scrollLeft, "Scroll Left", Scroll, UL, 515, 200, 62, 50
    Stylebits #1.scrollLeft, _BS_MULTILINE, 0, 0, 0
    Button #1.scrollRight, "Scroll Right", Scroll, UL, 515, 280, 62, 50
    Stylebits #1.scrollRight, _BS_MULTILINE, 0, 0, 0

    Open "Scrolling a GraphicBox with API Call" for Window as #1
    #1, "Trapclose EndDemo"

'Draw a grid
    #1, "Font Times_New_Roman 12 Bold"
    #1.g, "Down; Color Pink; Backcolor Buttonface; Fill Buttonface"
    For x = 50 to 2000 Step 50
        #1.g, "Line ";x;" 50 ";x;" 1250"
    Next x
    For y = 50 to 1200 Step 50
        #1.g, "Line 50 ";y;" 2000 ";y
    Next y
    #1.g, "Color Black"
    For x = 50 to 2000 Step 50
        n = x - 20 + 5 * (x > 50) + 12 * (x = 50)
        #1.g, "Place ";n;" 40"
        #1.g, "\";x
    Next x
    For y = 100 to 1200 Step 50
        n = 10 + 5 * (x > 50) + 12 * (x = 50)
        #1.g, "Place ";n;" ";y + 4
        #1.g, "\";y
    Next y
    #1.g, "Flush"
    Wait

    Sub EndDemo handle$
        Close #1
        End
        End Sub

    Sub Scroll handle$
        Select Case
            Case Instr(handle$, "Up") > 1
                ScrollDirection = _WM_VSCROLL
                ScrollAmount = _SB_PAGEUP 'or _SB_LINEUP
            Case Instr(handle$, "Down") > 1
                ScrollDirection = _WM_VSCROLL
                ScrollAmount = _SB_PAGEDOWN 'or _SB_LINEDOWN
            Case Instr(handle$, "Left") > 1
                ScrollDirection = _WM_HSCROLL
                ScrollAmount = _SB_PAGELEFT 'or _SB_LINELEFT
            Case Instr(handle$, "Right") > 1
                ScrollDirection = _WM_HSCROLL
                ScrollAmount = _SB_PAGERIGHT 'or _SB_LINERIGHT
        End Select
        Call ScrollBox hWnd(#1.g), ScrollDirection, ScrollAmount
        End Sub

    Sub ScrollBox handle, ScrollDirection, ScrollAmount
        Calldll #user32, "SendMessageA", _
        handle as Ulong, _
        ScrollDirection as Long, _
        ScrollAmount as Long, _
        0 as Long, _
        result as Long
        End Sub

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